tokarev,
It's good to hear that our exploratory tinkering has paid off for you. As a result of your outcome, I went ahead and tried the perpendicular slot-to-hole alignment again; and it's actually not as bad as I had recalled. The draw is a little harder than I prefer, but I can see why some people may like it. After a little more experimentation, I think that the battery's slotted center contact can be fairly considered as an effective draw adjustment screw.
As for the screwdriver thing ... after having been extremely cautious with my screwdriver at first, I got a good laugh at myself when I remembered the vacuum switch and its relevance. Nonetheless, being cautious is never a bad thing; especially when dealing with lithium-based
batteries.
Speaking of being cautious, anyone who chooses to experiment with the slot-to-hole alignment being discussed here should know that the slotted center contact has a small and important power wire soldered to it. So, if you turn it too much, then you will run the very high risk of breaking the wire to center contact connection, and end up with a battery that needs to be repaired. Consequently, if you feel the need to experiment despite this risk, then make sure that you limit your adjustment to no more than a 1/4 turn in either direction.
With your thread body holes at the 9 and 3 o'clock positions, the maximum range of slot adjustment should be between 9 and 12 o'clock.